The NRF's Emergency Support Function Annexes (ESFs) group capabilities and resources into functions most likely needed during an incident. A large-scale natural disaster or significant terrorist incident can require the activation of all ESFs. A localized flood or tornado might only require activation of a few ESFs.

Each ESF has one or two coordinating federal agencies that are in charge of orchestrating federal support and managing staff and resources for that functional area, and additional agencies that have supporting roles.